This invention relates to magnetostrictive materials and more particularly to rare earth-iron magnetostrictive materials.
It has recently become apparent that the primary loss mechanism in high power devices employing giant magnetostrictive materials is hysteresis losses. Even at low audio frequencies, this loss far exceeds the sum of all other losses, which include Cu-coil loss, Terfenol eddy current losses, and eddy current loses in the Cu and in d. c. biasing magnets. While the lowered efficiency may be a significant drawback, the most deleterious effect of the loss is often excessive heating, requiring increased complexity with associated increased costs to cool the device.
The desired new magnetostrictive transducer element should combine a very low magnetization hysteresis with a giant magnetostrictive effect. Moreover the transducer element should not be more expensive to make or operate than prior art transducer elements.